Aminoalkyl glucosaminide phosphates (AGPs) are synthetic ligands of the Toll-like Receptor 4 (TLR4). AGPs and their immunomodulating effects via TLR4 are disclosed in patent publications such as WO 2006/016997, WO 2001/090129, and/or U.S. Pat. No. 6,113,918 and have been reported in the literature. Additional AGP derivatives are disclosed in U.S. Pat. No. 7,129,219, U.S. Pat. No. 6,525,028 and U.S. Pat. No. 6,911,434. Certain AGPs act as agonists of TLR4, while others are recognized as TLR4 antagonists. AGPs are known to be useful as vaccine adjuvants and immunomodulators for stimulating cytokine production, activating macrophages, promoting innate immune response, and augmenting antibody production in immunized animals. Previously, AGPs as adjuvants and/or immunomodulators have principally been utilized in the form of an oil-in-water emulsion, typically using sterilized water and glycerol (approximately 2%). There is an on-going need to identify buffers that may be employed with these AGPs in pharmaceutical and/or adjuvant compositions.